Crystal Structure of Three Ionic Compounds of Levofloxacin

Abstract

The structures of three ionic compounds of levofloxacin (LevoH or Ci₁₈H₂₀FN₃O₄) − LevoH₃[CoCl₄]-H₂O (I), LevoH₃[ZnBr₄]·H₂O (II), LevoH₃[CuBr₄]-H₂O·(III) are determined. The crystals of I-III are monoclinic; in compound III, the particles are packed so that the direction of the screw axis does not coincide with the largest unit cell parameter. The asymmetric unit of the unit cell contains two LevoH₃²⁺ and CoCl₄²⁻ ions and two crystallization water molecules in I; two LevoH₃²⁺ and MBr₄²⁻ (M = Cu, Zn) ions and two crystallization water molecules in II and III. The absolute structure of the crystals and the configuration of the chiral center of the levofloxacinium cation S are determined. The structures are stabilized by multiple hydrogen bonds, X−Y π and π-π interactions.